1. Field
The following description relates to a transceiver applying switching of a phase locked loop (PLL) and a phase noise improvement technique.
2. Description of Related Art
Generally, a radio frequency (RF) transceiver consumes the most power in an ultra low power (ULP) system. In particular, RF blocks of an RF analog device consume the most power in the RF transceiver. In the ULP system, an amplifier consumes less power due to a short signal arrival distance, whereas a voltage controlled oscillator (VCO) and a PLL consume more power. Furthermore, because power is applied to the PLL and the VCO almost all the time in most RF transceivers, they consume a large amount of the power used by the overall system.
Moreover, interference may be generated through various routes when a plurality of VCOs are not sufficiently isolated from one another. When the amplitudes of the interference signals are greater than the amplitudes of the received signals, the received signals may fail to be recognized by the transceiver.